Shares in tobacco firm Lorillard closed up 10.6% at $87.11 after fears of a US ban on menthol cigarettes were reduced.
A report by the US Food and Drug Administration (FDA) called for more research before a decision could be taken, rather than saying a ban would help improve public health.
Lorillard owns the best-selling Newport menthol cigarette brand.
MF Global Holdings analyst Mark McMinimy said it was “very unlikely” the FDA would ban menthol cigarettes.
“If you’re calling for more research, how can you call for something like removing menthol cigarettes from the market, which seems very final?”
A draft report had included the following phrase from an advisory panel: “Removal of menthol cigarettes from the marketplace would benefit public health in the United States.”
That phrase had been removed before the latest report was published.
“It lifted uncertainty on the stock,” said Davenport & Company analyst Ann Gurkin.
“The uncertainty as to what the committee would recommend has been laying on the stock, and now we know the recommendation.”
Menthol cigarettes make up almost a third of the $83bn US cigarette market, according to Euromonitor International.
Lorillard’s Newport brand accounts for 85% of the company’s sales.
External advisers to the FDA had found that the availability of menthol cigarettes “increases initiation and reduces cessation”.
“Of particular concern was the high rate of menthol cigarette smoking among youth and the trend over the last decade of increasing menthol cigarette smoking among 12 to 17 year olds, even as smoking of non-menthol cigarettes declines,” the draft report written by the advisers said.
Experts say the case is about race as well as about public health as US African-Americans tend to prefer menthol cigarettes and statistically they suffer more from diseases related to smoking than white people do.
In 2009, cigarettes with chocolate, cherry, vanilla and other flavours were banned.